When a tooth must be extracted due to external injury or dental caries, a dental prosthesis is used to form the natural inter-dental papilla or gingiva and recover mastication, pronunciation and aesthetic functions. The dental prosthesis is referred to as an artificial tooth or a false tooth. Further, the dental prosthesis means an artificial substitute for a missing natural tooth or tissue associated therewith. Such a dental prosthesis has been essentially used to prevent a tooth adjacent to an extracted tooth from moving to an abnormal location during dental treatment period.
Meanwhile, all dental prostheses have been manufactured through the manual operation of a dental technician. However, recently, technology dealing with a prosthesis manufacturing machine which is capable of more efficiently and precisely manufacturing a dental prosthesis has been developed.
For example, Japanese Patent Laid-Open Publication No. 2002-0273655 disclosed a dental prosthesis manufacturing machine using a structure for measuring the accurate positional data of first and second machining tools which machine the workpiece of the dental prosthesis. Further, Japanese Patent Laid-Open Publication No. 2008-0509745 disclosed a dental prosthesis manufacturing machine using a structure which axially offsets first and second spindles from each other so as to improve the accuracy of prosthesis manufacturing work.
The conventional machines are advantageous in that they improve the manufacturing accuracy of a dental prosthesis. However, when a portion requiring a high degree of accuracy in the manufacturing process of a dental prosthesis is machined using the conventional machines, existing machining tools are disconnected from the spindles, and thereafter precision machining tools are attached to the spindles to perform precision machining work. Alternatively, the workpiece is transferred to another dental prosthesis manufacturing machine which conducts more precise machining work. Thus, the conventional machines are problematic in that it is complicated to manufacture a dental prosthesis. Such a process is disadvantageous in terms of time and cost.